Sub Trigram()
Dim R As Range
Sheets("utilisable").Activate
Range("B1").Select
Set R = Sheets("utilise").Range("A1", Sheets("utilise").Range("A65536").End(xlUp))
For Each cel In Range("A1", Range("A65536").End(xlUp))
If IsError(Application.Match(cel, R, 0)) Then cel.Select: Exit Sub
Next
End Sub